A standard wet-cell battery of the type used to start an internal-combustion engine of an automotive vehicle or used to power an electric lift truck or the like has a housing or casing subdivided by partitions into a plurality of individual compartments or cells each filled with a respective bath of an electrolyte, normally a liquid acid. Each cell further contains a plurality of positive electrode elements and a plurality of negative electrode elements interleaved therewith. All the positive elements of each cell are connected together by a positive bus bar and all the negative elements by a negative bus bar. The negative bar of the cell at one end of the battery is connected to a negative terminal on the battery top, and the positive bar of the cell at the opposite battery end is connected to a positive terminal at the opposite end of the battery top. The intervening positive and negative buses are connected together plus-to-minus with the cells in series, thereby increasing output voltage. These elements are of lead, nickel, or cadmium and react with the electrolyte and each other to produce electricity.
As described in U.S. Pat. No. 3,853,626 and in German patent document No. 3,011,836, it is possible to use expanded metal to make the electrode elements instead of the cast construction once employed. Expanded metal, which is made by forming a plurality of rows of evenly spaced slits with the slits staggered from row to row, and then pulling the metal perpendicular to the slits to open them up into holes, can be made extremely cheaply from low-cost rolled sheet metal.
In this type of wet-cell battery individual rectangles of the expanded metal are aligned with the cells. These cells are elongated transversely of the battery, so all the electrode plates therefore are parallel to one another and perpendicular to the battery. Typically there are between eight and fourteen such expanded-metal plates in each cell, so that a six-cell battery has between 48 and 84 plates overall.
It is further known to arrange the electrode plates parallel to the battery, that is transversely of the respective cells. Each cell can hold up to 66 individual small such plates, so that a six-cell battery will have 396 expanded-metal electrode plates overall. Such construction substantially reduces the internal resistance of the plates, since the path from the furthest point on each small plate to the respective bus is inherently short. As a result the high-current output of such a battery is considerable. In such arrangements, however, the plates, bus bars, and terminals are all cast. This allows all of the parts to be positioned accurately and eliminates complicated fabrication procedures, but is a costly style of manufacture and uses a substantial mass of valuable metal. In fact the increased cost of the cast metal more than outweighs the increases in efficiency.